The present invention generally relates to the fabrication of integrated circuits. More particularly, the invention provides a high pressure release device for handling sudden bursts of excess pressure within a semiconductor processing chamber. The present invention is particularly useful for releasing the pressure within chemical vapor deposition (CVD) chambers, but also finds uses in ion implantation chambers, etching chambers, and other chamber types.
High density integrated circuits, commonly termed VLSI devices, are typically formed on semiconductor wafers by subjecting the wafers to a number of deposition, masking, doping and/or etching processes. The wafers are placed onto a pedestal or susceptor within a process chamber and process gas(es) delivered into the chamber perform the various deposition and etching steps on the wafer. For example, one typical process involves delivering silane (SiH.sub.4) and nitrogen (N.sub.2) into the process chamber while applying RF energy to form a plasma for depositing silicon nitride (Si.sub.3 N.sub.4) on the wafer. During each step, once the appropriate layers have been deposited and/or removed from the wafer, the remaining plasma and gas residue are withdrawn from the process chamber by a suitable vacuum source, such as a pump.
Occasionally, due to an error in the combination of the process gases or the presence of undesired reagents in the processing chamber, an explosion or a sudden burst of pressure may occur in the semiconductor processing chamber. The force from the explosion may damage gas flow valves and other moving parts upstream and downstream of the processing chamber. The resulting explosion also typically forces some portion of the chamber, usually the lid, to break its air-tight seal with the chamber, releasing process gas into the surrounding environment.
In addition to the internal damage sustained by the chamber, the release of these chemicals into the open environment poses a secondary and sometimes more serious health risk to those people working near the chamber. In many instances, the process gases and chemicals used inside the semiconductor processing chamber are toxic to the human body or explosive when exposed to ambient air or water.
Therefore, improved safety methods and apparatus for controlling sudden explosions which may occur within a semiconductor processing chamber are needed in the semiconductor manufacturing industry. To date, the use of pressure fail-safe mechanisms in processing chambers is an important, yet generally unaddressed consideration. These methods and apparatus should improve work conditions for those people near the processing chamber by preventing the release of process gases into the open environment. These methods and apparatus should further minimize internal damage to the chamber by relieving pressure as it builds from the explosion.